The steps of St Paul's Cathedral have in their time been commandeered by royalty, by tourists for photographs, and by vergers' wives selling themselves. Admittedly, that last part hasn't happened for a while and was in a previous version of the building, but the point remains: St Paul's is an august, iconic and yet adaptable backdrop for performance. Especially if it isn't raining.

Unfortunately, the first two performances of choreographer Shobana Jeyasingh's site-specific dance piece 2Step had to be called off, but the dancers finally grabbed a moment between showers to perform on Thursday. In the hard, cold light of a damp London lunchtime, the dancers looked all too real, and, like the audience, exposed: 20 students from the Central School of Ballet, Laban and the London Contemporary Dance School with white legs in windblown flimsy red costumes.

Steps - of the stone kind - present a particular problem for dance: you wouldn't want to leap wildly or turn too fast. 2Step was, of necessity, relatively static, but Jeyasingh trained in Bharata Natyam, a grounded form of Indian classical dance with bent knees, so the setting was an opportunity for formalism, as well as a constraint, and she used the levels to create almost mathematical patterns up and down, in lines, couples and trios.

On the space of a narrow step, the dancers' splayed knees, shrugging shoulders and jutting hips could look trapped, as if they were frogs preparing to leap but could never quite take off. There was a fair amount of lifting, but it was slow and yogic rather than acrobatic. The piece was at its best when the solidity of the dancers' bottom halves was offset by upper body fluidity, by expressive arms, hands, necks. The most beguiling were those few who could seem to float away, so fine and light did their upper limbs seem.

The music was a mixture of a symphony by the Polish 20th-century composer Andrzej Panufnik, a sextet by the minimalist Steve Reich, some Swedish psychedelic trance from Vibrasphere of Uppsala and Midival Punditz, the bhangra-electronic duo from Delhi. It was a counterpoint to the rather British establishment setting: enigmatic, unsettling and liable to increase the feeling that here was a fusion that opened up possibilities but could also be very confusing.

2Step was commissioned and produced by the City of London Festival, which is using the west front of St Paul's for a number of events this year, including jugglers from the London Youth Circus and (sorry, but you've already missed this) a performance of Alphorns. The piece also came under the umbrella of Big Dance, a GLA-backed week showcasing the many dance initiatives (mainly participative) in the capital. It's to be hoped that, by next year, Big Dance will have sorted out its utterly impenetrable website.